Stopper for closing containers, such as bottles, flasks and the like



Jan. 5, 1965 HRER 3,164,278 STOPPER FOR CLOSING CONTAINERS, SUCH ASBOTTLES, FLASKS AND THE LIKE Filed July 25, 1963' ATTYS,

United States Patent M STOPPER FOR (ILQSHNG CONTAINERS, SUQH AS BOTTLES,FLASKS AND THE LIKE Hardy Lohrer, 16 Heilmundstrasse, Wieshaden, GermanyFiled Italy 23, 1963, Ser. No. 297,112 Claims priority, applicationGermany, May 9, 1963, L 44,850 1 Claim. (Cl. 21541) This inventionrelates to a stopper of elastic material for closing containers, such asbottles, flasks and the like, comprising an external cap portion and aninner hollow plug portion with an open bottom and a thin-walled neckexternally coned to form a thicker wall portion tapering into asharp-edged bottom lip.

A known type of stopper of plastic material for bottles and so forthcomprises a plug provided with sealing ribs which are to be kept so thinthat the plug can be inserted into the neck of a bottle by hand withoutconsiderable effort. However, in this form of construction the internalpressure to which the plug is subjected causes fatigue so that the gripof the plug inside the neck of the bottle quickly relaxes. Such plugsare not therefore able to provide completely reliable and permanentgas-tight seals for bottles in which the internal width of the neck islikely to vary within wider tolerational limits. Moreover, in order toachieve as tight a seal as is possible the top of the stopper must beformed with a slight depression above the top of the plug, saiddepression being pushed fiat from the inside by the permanent outwardthrust of the plug.

Another type of stopper which has been proposed for sealing bottles,flasks and the like has an inner plug with an annular bulge which taperstowards a bottom terminal lip, and is therefore capable of taking upeven major tolerational variations in the internal width of the neck.The thinness of the walls of the plug prevents the sealing pressure ofits bulge from being transmitted to the thick floor of the top of thestopper, so that the provision of a shallow depression therein can bedispensed with.

Nevertheless, this type of stopper also fails in some cases to providean absolutely satisfactory seal, particularly on mineral water bottlescontaining a further addition of artificially introduced carbon dioxide.

Although for the purpose of tests a spontaneous evolution of a majorpart of the carbon dioxide contained in the water can be induced by theaddition of small amounts of a fine-grained material, such as sugar andparticularly common salt, exact measurements could not be made othrewisethan by providing the bottles with holes for the attachment of thenecessary gauges. In this way it was found that a natural mineral watermay contain more than 8000 mg. of free carbon dioxide and that afteraddition of further carbon dioxide at a gauge pressure of 2 ats, thepressure inside the sealed bottle may rise to 8.5 ats. In transportationtests the vibration even caused the gauge pressure inside the bottles atsummer temperatures to rise to the considerable level of 12 ats. Theknown types of stopper were not always able to withstand pressures ofthis magnitude.

It is therefore the object of the present invention to provide a stopperof elastic material which comprises a skirted cap for embracing themouth of the bottle and a plug which is insertable into the mouth of thebottle, intended particularly for bottles containing a liquid under veryhigh pressure or capable of developing very high pressures under certainunfavourable conditions. The proposed stopper is further intended toprovide an absolutely reliable gas-tight seal for lengthy periods. Theproposed stopper is completely unobjectionable from the point of view ofhygiene, consisting of a small quantity 3,lh4,278 Patented Jan. 5, 1965of inert material, and it is also suitable for rapid mass production atlow price.

The invention provides a stopper of elastic material for containers suchas bottles, flasks and the like, which comprises an external cap and aninternal hollow open-bottomed plug with a thin-walled neck which isexternally coned to form a thickened portion tapering towards a sharpedged bottom lip and an internal surface merging with a large radiusinto the underside of the top of the cap, whereas the external surfacemerges with a small radius into the underside of the cap at the top ofthe space intervening between the plug and the skirt of the cap.

In an alternative form of construction the inside of the hollow plugmerges at the top into a concave spherical surface which forms theunderside of the centre portion of the cap.

Another feature of the stopper as proposed by the invention is that thesurface which forms the top of the cavity in the hollow plug ispreferably located at a lower level than the annular surface forming thetop of the space between the outside of the plug and the skirt of thecap, so that the centre portion of the cap above the plug is thickerthan the annular portion adjacent the skirt.

in the above proposed forms of construction the top of the cavity of thehollow plug forms a circular or like are in cross section. It will beunderstood that this curve might be a parabolic or some other are whichhas axially symmetrical branches and that any such modification isintended to be included within the scope of the present invention,provided always that the radius of the curve merging into the insidewalls of the plug and representing the genrator of the body ofrevolution defining the surface at the top of said cavity is greaterthan the radius of the are between the outside of the plug and theunderside of the top of the cap.

Two preferred embodiments of the invention will now be described by wayof example and with reference to the accompanying drawings, in which:

FIG. 1 is an axial section of a stopper in which the top of the cavityinside the plug is a surface of revolution generated by a catenarycurve, and

FIG. 2 is an alternative embodiment in which the generating curve is acircular arc.

FIG. 1 shows 'a stopper which comprises an external cap with a skirt 1formed with an internal bulbous ring 2 which engages the underside ofthe projecting rim of the mouth of the bottle, flask or the like. Belowthis ring 2 the skirt 1 has an extension 3 which can be torn off, andwhich to this end is separated from the upper part of the skirt by adeep indentation 4. The horizontal cap portion 6 of the cap merges intothe skirt 1 with a short radius 5.

Below the horizontal cap portion 6 the stopper is formed with a hollowplug 7 with an open bottom. This plug 7 has a thin-walled neck 8 whichis externally coned to form a thickened portion 16 tapering into a sharpedged lip 9. The internal surface 11 of the hollow plug 7 merges intothe underside 14 of the cap portion 6 with a large radius 12. The outersurface 15 of the plug 7 above the neck merges into the annular part 18of the underside of the cap portion 6 adjacent the skirt with a smallradius curve 16.

In the second embodiment shown in FIG. 2 the internal surface 11 of theplug 7 forms a spherical surface underneath the cap portion 6.

The surface 14 at the top of the cavity 13 in plug 7 is formed at alower level than the top of space 17 between the plug 7 and the skirt 1of the cap.

In the embodiment in which the upper end of the cavity 13 in the hollowplug 7 is a concave spherical surface the apex of the spherical surfaceis still located below the level of the surface which forms the top ofthe space J between the plug"7 and the skirt It. Consequently theWeakest part of the cap portion 6 directly above the plug 7 is thickerthan the annular portion oi the cap adjacent its skirt 1.

The described conformation of the stopper proposed by the inventiontherefore permits the stopper to be readily thrust into the mouth of abottle and the pressure inside the bottle will press the outside of theping against the inside of the mouth of the bottle. Extensiveexperiments have revealed that the described stopper will in factsecurely and tightly seal bottles containing extremely high internalpressures.

I claim:

A stopper of elastic material for containers comp-rising an external caphaving an end Wall terminating in a depending peripheral skirt, saidskirt including an inwardly directed peripheral locking bead, and aninternal peripheral indentation below said bead whereby a lowermostskirt portion of said skirt can be removed incidental to the removal ofthe stopper from a container with which the stopper is associated, saidend wall having a central port-ion joined to said skirt by a top Wallportion having a thickness appreciably less than the thickness of said:central portion, an integral open-bottomed plug depending axiallydownwardly from said thickened central portion of said end wall andterminating short of a lowermost edge of said shirt, said plug havinginternal and external surfaces, said internal surface beingsubstantially cylindrical and merging with a large radius into thecentral portion of said end wall, said external surface having a firstsurface portion flaring radially downwardly and outwardly and a secondsurface portion flaring radially inwardly and downwardly to define withsaid internal SE11- face a relatively sharp edged conical bottom lip,said internal and external surfaces setting oil Wall thicknesse of saidplug which are relatively thin adjacent said central portion of the endWall, thicker to a maximum at the juncture of the first and secondflaring portions, and thin appreciably at said bottom lip.

References tilted by the Examiner UNITED STATES PATENTS 1,946,981 2/34Lower 2l54l X 2,717,728 9/55 Gray 215-47 2,772,862 12/56 Wozdatt et al2l5-4l 2,894,654 7/57 Lohrer 215-4l 926,806 3/60 Streng et a1 2l5463,074,579 1/63 Killer 215-41 FRANKLIN T. GARRETT, Primary Examiner.

THERGN E. CONDON, Examiner.

